Benzotriazole Photostabilizers: Nitration of Tinuvin P

Abstract

Nitration of the commercial photostabilizer Tinuvin P, 2-(21-hydroxy-5′-methylphenyl)- 2H-benzotriazole,* has been shown to yield 2-(2′-hydroxy-5′-methyl-3′-nitrophenol)-2H-benzotriazole. The anion of this nitro compound is intensely coloured and may be the cause of yellowing of polymers in which Tinuvin P has been incorporated.